For fans of dry yeasts: in the latest William's Brewing
catalog/Newsletter, There is an article by William Moore titled "Dry
Yeast Revisited." Williams, for those who haven't heard of them, is a
supplier (and vocal advocate) of liquid yeast cultures. They recently
tested a bunch of dry yeasts (along side their liquid yeasts) to see
if it is "possible to brew truly good beer with convenient dry
yeasts..." (a question I thought had been settled long ago).

I won't quote the whole article, but to summarize, they found
that, if treated properly, dry yeast makes dandy beer, but not as good
as their liquid yeasts.

To quote:
"It appears most home brewers have been abusing their
dry yeast. Dry yeast should only be rehydrated in warm
water between 90 and 100 degrees F. Use 1/2 cup of
water for every 14 grams of dry yeast. Rehydrating
dried yeast in wort can shock and injure the yeast,
because wort is relatively acid,and dry yeast prefers
a neutral rehydration medium. It is vital to the
future flavor of the beer that dry yeast be rehydrated
in warm water only.

Ideally, rehydration should take place for 15 minutes
before pitching. When pitching, it is very important
that the freshly revived yeast is not temperature
shocked; a temperature change of more than 17 degrees
will cause the yeast to both emit off-flavor compounds
and slow down, perhaps halting all activity if the
shock is great enough. If your yeast is at 90 degrees
F. and your wort is at 65, add a half a cup of wort to
your yeast to become acclimated to the new
temperature, and then pitch into the 65 degree
fermenter."

So I've been doing it right all along and thought I was being
lazy! The above advice is definitely contrary to that I've seen in
several books on homebrewing, so if this starts a controversy, it
could take quite a while to settle out.